Children with psychopathic traits represent a distinct group of antisocial youth who engage in more severe and frequent antisocial behavior. A recently developed theoretical framework suggests that psychopathic traits may result from an imbalance in two overarching hormone systems that regulate sensitivity to punishment and reward, leading to fearlessness, insensitivity to punishment, reward-seeking, and aggression. The proposed study will be the first to test this conceptual framework in children with psychopathy. Because the hormone systems involved are highly interconnected and mutually antagonistic, the study will simultaneously assess hormones from multiple systems, including the hypothalamic-pituitary- adrenal axis, sympathetic nervous system, and gonadal system to gain a more complete understanding of how these systems may work together to produce psychopathic traits. The specific aims of the study are to assess the relationship between childhood psychopathy and (1) resting hormone levels, (2) hormone reactivity to a stressor, and (3) interactions between different hormone systems. A final aim is to assess the effect of specific features of psychopathy on hormone levels. In a sample of 11-year-old participants (115 male, 115 female), the hormones Cortisol, testosterone, alpha-amylase, and DHEA will be assessed at rest and time points following a stressor involving social and uncontrollable aspects. Childhood psychopathic traits will be assessed using the Antisocial Process Screening Device, RELEVANCE. Results from approximately a decade of research suggest that childhood psychopathic traits predict more severe, pervasive, and stable constellations of conduct problems above and beyond other known predictors and classification approaches (Kotler &McMahon, 2005). Adult psychopathy is present in approximately 15-20% of criminal offenders and is one of the strongest predictors of violent recidivism (Skilling et al., 2002). Children with psychopathic traits are more resistant to treatment approaches than other antisocial youth. The study of hormones may open doors to new possibilities for treatment. If abnormalities in hormone systems are found to exist, it may be possible to restore a proper balance via hormone manipulations. Such a biological intervention is potentially a key step in improving the responsivity of children with psychopathic traits so that other forms of treatment that have previously failed may begin to have efficacy. By studying these traits in a relatively young age group, we may be able to intervene early, when this group of potentially chronic, severe offenders may be more amenable to intervention.